Docker Port Forwarding - django

Question

I am trying to run my django application in a docker container. I am using uWSGI to serve the django application, and also have a celery worker running in the background. These processes are started by supervisord.
The problem that I am having is that I am unable to see the application on the port that I would expect to see it on. I am exposing port 8080 and running the uwsgi process on 8080, but cannot find my application in a browser at the ip address $(boot2docker ip):8080. I just get Google Chrome's 'This webpage is not available'. (I am using a Mac, so I need to get the boot2docker ip address). The container is clearly running, and reports that my uwsgi and celery processes are both successfully running as well.
When I run docker exec CONTAINER_ID curl localhost:8080 I get a response like
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 21 0 21 0 0 3150 0 --:--:-- --:--:-- --:--:-- 3500
... so it seems like the container is accepting connections on port 8080.
When I run docker exec CONTAINER_ID netstat -lpn |grep :8080 I get tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 11/uwsgi
When I run docker inspect CONTAINER_ID I get the following:
[{
"AppArmorProfile": "",
"Args": [
"-c",
"/home/docker/code/supervisor-app.conf"
],
"Config": {
"AttachStderr": true,
"AttachStdin": false,
"AttachStdout": true,
"Cmd": [
"supervisord",
"-c",
"/home/docker/code/supervisor-app.conf"
],
"CpuShares": 0,
"Cpuset": "",
"Domainname": "",
"Entrypoint": null,
"Env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"env=staging"
],
"ExposedPorts": {
"8080/tcp": {}
},
"Hostname": "21443d8a16df",
"Image": "vitru",
"Memory": 0,
"MemorySwap": 0,
"NetworkDisabled": false,
"OnBuild": null,
"OpenStdin": false,
"PortSpecs": null,
"StdinOnce": false,
"Tty": false,
"User": "",
"Volumes": null,
"WorkingDir": ""
},
"Created": "2014-12-27T01:00:22.390065668Z",
"Driver": "aufs",
"ExecDriver": "native-0.2",
"HostConfig": {
"Binds": null,
"CapAdd": null,
"CapDrop": null,
"ContainerIDFile": "",
"Devices": [],
"Dns": null,
"DnsSearch": null,
"ExtraHosts": null,
"Links": null,
"LxcConf": [],
"NetworkMode": "bridge",
"PortBindings": {},
"Privileged": false,
"PublishAllPorts": false,
"RestartPolicy": {
"MaximumRetryCount": 0,
"Name": ""
},
"SecurityOpt": null,
"VolumesFrom": null
},
"HostnamePath": "/mnt/sda1/var/lib/docker/containers/21443d8a16df8e2911ae66d5d31341728d76ae080e068a5bb1dd48863febb607/hostname",
"HostsPath": "/mnt/sda1/var/lib/docker/containers/21443d8a16df8e2911ae66d5d31341728d76ae080e068a5bb1dd48863febb607/hosts",
"Id": "21443d8a16df8e2911ae66d5d31341728d76ae080e068a5bb1dd48863febb607",
"Image": "de52fbada520519793e348b60b608f7db514eef7fd436df4542710184c1ecb7f",
"MountLabel": "",
"Name": "/suspicious_fermat",
"NetworkSettings": {
"Bridge": "docker0",
"Gateway": "172.17.42.1",
"IPAddress": "172.17.0.87",
"IPPrefixLen": 16,
"MacAddress": "02:42:ac:11:00:57",
"PortMapping": null,
"Ports": {
"8080/tcp": null
}
},
"Path": "supervisord",
"ProcessLabel": "",
"ResolvConfPath": "/mnt/sda1/var/lib/docker/containers/21443d8a16df8e2911ae66d5d31341728d76ae080e068a5bb1dd48863febb607/resolv.conf",
"State": {
"ExitCode": 0,
"FinishedAt": "0001-01-01T00:00:00Z",
"Paused": false,
"Pid": 16230,
"Restarting": false,
"Running": true,
"StartedAt": "2014-12-27T01:00:22.661588847Z"
},
"Volumes": {},
"VolumesRW": {}
}
]
As someone not terribly fluent in Docker, I'm not really sure what all that means. Maybe there is a clue in there as to why I cannot connect to my server?
Here is my Dockerfile, so you can see if I'm doing anything blatantly wrong in there.
FROM ubuntu:14.04
# Get most recent apt-get
RUN apt-get -y update
# Install python and other tools
RUN apt-get install -y tar git curl nano wget dialog net-tools build-essential
RUN apt-get install -y python3 python3-dev python-distribute
RUN apt-get install -y nginx supervisor
# Get Python3 version of pip
RUN apt-get -y install python3-setuptools
RUN easy_install3 pip
RUN pip install uwsgi
RUN apt-get install -y python-software-properties
# Install GEOS
RUN apt-get -y install binutils libproj-dev gdal-bin
# Install node.js
RUN apt-get install -y nodejs npm
# Install postgresql dependencies
RUN apt-get update && \
apt-get install -y postgresql libpq-dev && \
rm -rf /var/lib/apt/lists
# Install pylibmc dependencies
RUN apt-get update
RUN apt-get install -y libmemcached-dev zlib1g-dev libssl-dev
ADD . /home/docker/code
# Setup config files
RUN ln -s /home/docker/code/supervisor-app.conf /etc/supervisor/conf.d/
# Create virtualenv and run pip install
RUN pip install -r /home/docker/code/vitru/requirements.txt
# Create directory for logs
RUN mkdir -p /var/logs
# Set environment as staging
ENV env staging
EXPOSE 8080
# The supervisor conf file starts uwsgi on port 8080 and starts a celeryd worker
CMD ["supervisord", "-c", "/home/docker/code/supervisor-app.conf"]

Answer 1

I believe the problem you have is that EXPOSE only makes the ports available between containers... not to the host system. See docs here:
https://docs.docker.com/reference/builder/#expose
You need to "publish" the port via the -p flag for docker run command:
https://docs.docker.com/reference/run/#expose-incoming-ports
There is a similar distinction in Fig, if you were using it, between expose and ports directives in the fig.yml file.